In this book, we will explore the emulation of human thought, capable of dealing with uncertainties, ambiguities, and contradictions. The human thought can be expressed in rules. To handle uncertainties, ambiguities, and contradictions, we will use fuzzy system techniques, implemented by a fuzzy expert system. Expert systems are computer programs, designed to make available some of the skills of an expert to non-experts. The hundreds of edited works and tens of thousands of archival papers show clearly that this is a rapidly growing technology, where new discoveries are being published every month. It remains our fervent hope that this introductory textbook will assist students and practicing professionals to learn, to apply, and to be comfortable with fuzzy expert system and fuzzy logic. We implements two real case study with more detail, so the reader being able to create desired fuzzy expert system after the short period of reading this book.